Version Numbers and Build Codes and ModJoy: A Guide for Older Android Devices

https://gamerapkhouse.opalvector.com/posts/frequently-asked-questions-about-account-login-security-and-apkmodjoy

Older Android devices can still be useful, but they often need more care with app versions and resource use. Version numbers help people recognize releases, while build codes give Android a numeric way to order app builds